Wood products have been used as utility poles, railway ties, and construction materials in a wide variety of industries. Without proper treatment, wood products deteriorate and are susceptible to weathering, insects (e.g., termites, carpenter ants, and beetles), marine borers (e.g., mollusks and crustaceans), bacteria, and fungi (e.g., stains, white rot, soft rot, and brown rot). Wood treatment is required to prevent these problems. More effective wood treatment compositions are needed.
Preservatives used to treat wood, such as creosote and pentachlorophenol (PCP) containing compositions are effective at preserving wood, but may emit naphthalene and other volatile organic compounds (VOCs) that are associated with petroleum and coal tar distillates. Some of these volatile compounds are toxic and/or have unpleasant odors. In particular, these VOCs are both a health risk and a nuisance for the plants using either creosote or PCP in diesel carrier oil.
During wood-treatment processes, creosote-based or PCP/diesel-based preservatives are brought to elevated temperatures and the VOCs are released to the atmosphere. Consequently, many plants are required to install expensive air scrubbers and incineration units which have a high capital cost. Further, the sequestered VOCs must be contained and disposed, further adding to production costs and potential hazards.
The VOCs also tend to persist in the treated wood products and off-gas from the wood products over time. This gradual emission of VOCs from treated wood yields unpleasant odors that are not suitable for populated areas. As such, more active and effective odor suppressants are needed. The discovery of more active odor suppressants will yield wood preservative compositions that are more concentrated in creosote and/or PCP/diesel without the unacceptably high levels of odors and VOCs that are currently attributed to these chemicals.